Chalicotheriidae

Chalicotheriidae (from Ancient Greek χάλιξ (khálix), meaning "gravel", and θηρίον (theríon), meaning "beast") is an extinct family of herbivorous, perissodactyl mammals. Unlike living odd-toed ungulates, chalicotheres bore large claws on their hands rather than hooves, thought to have been used for grasping vegetation, with their dentition being adapted for browsing. The family is known from the Oligocene to the Pleistocene, reached its greatest diversity in the Miocene, and is known from Asia, Europe, Africa and North America. Asia appears to have been the main centre of diversification for the group. Chalicotheriids are usually divided into two subfamilies, Chalicotheriinae and Schizotheriinae, which differed in the skull, teeth and limbs. Chalicotheriines generally had much longer forelimbs than hindlimbs and are usually interpreted as more specialised browsers of wooded habitats, whereas schizotheriines had more even limb proportions and appear to have occupied a broader range of environments. Derived schizotheriines also developed the distinctive fused phalanges known as the duplex bone. Microwear and mesowear studies indicate that chalicotheriids were browsers rather than grazers, feeding mainly on leaves and also on tougher plant foods such as bark, twigs, and in some taxa fruit or other hard items. Their unusual claws are therefore generally interpreted as part of a specialised browsing adaptation rather than evidence of a primarily digging lifestyle.